Method of making flexible conduits



March 1931- E. G. KIMMICH METHOD OF MAKING FLEXIBLE CONDUITS OriginalFiled Allg- 1926 gwnloi min/u,

vlrlllllli amaze/6 Patented Mar. 17, 1931 UNITED STATES EIMER G.

PATENT OFFICE KIMMIOH, F AKRON, OHIO, ASSIGNOR TO THE GOODYEAR TIRE &BUB- BER COMPANY, OF AKRON, OHIO, A CORPORATION 'OF OHIO i METHOD OFMAKING FLEXIBLE CONDUITS Original application filed August 3, 1926,Serial No.

126,810. Divided and this application filed October 20,1927. Serial No.227,50

- supple conduit which is capable of with- "structe'd that they couldnot withstand externally applied normal loads, although theyv standingheavily imposed radial loads.

provide an efiicient method of making a highly flexible and supple hoseor conduit which is capable of withstanding loads applied eitherradially inwardly or outwardly.

- 0 Additional objects and advantages will This application is adivision of my applibecome apparent from the followin detailed cationSerial No". 126,810, filed August 3,1926.

Flexible tubing is often utilized for conveying finely divided material,such as grain or dust, by employing suction through the conduit. Hose ofthis character is also useful in conveying liquids, such as water fromthe holds of ships. It is also employed to advantage for conductingfluid under pressure, such; for example, as compressed air to apneumatically operated tool. In each of these applications, a highlyflexible hose of light weight is desirable, as the service in which itis employed is of such nature as to require a continual change in theposition of the conduit.

It is to be noted that flexible conduits should have a high strength ina radial direction, to prevent bursting with attendant loss. Hoseemployed for conveying dust is subjected to a high atmospheric pressureapplied radially toward the center. Hose utilized for conveying airunder pressure must, however, withstand a high pressure which isdirected radially outwardly. Flexible conduits employed for conveyingliquids must not only be sufficiently strong to withstand the internalnormal pressure, but they must be so constructed that they will notburst when the conduit is bent with the liquid confined therein. Thisrequirement necessitates the provision of a tubingwhich may not only bebent readily, but which also has a high degree of elasticity.

Various types of flexible conduits have been proposed, but none of them,so far as I am aware, has been suitable for use in all of the classes ofservice illustrated by the foregoing examples. In certain constructions,strength has been sacrificed to attain flexibility, while other conduitshave been so con- 4 could sustain high internal ressures.

It is one of the objects 0 the invention to description of a preferredformo ractics ing the invention,'wherein reference 1s made to theaccompanying drawing, in which:

Fig. 1 is a fragmentary plan view of the conduit as .it appears duringan early stage of its construction, parts being broken away for the sakeof clearness;

Fig. 2 is a fragmentary plan view of the conduit as it appears in a moreadvanced stage of construction, parts being broken away for ample, as arope 11, of suitable diameter to and the ends are secured thereto by anysuit able means; for example, biy means of a piece of tape. It has beenound that the proper flexibility may be imparted to the hose, for thedifferent diameters in which it may be constructed, by spacing the turnsat a distance equal to about twice the diameter ofthe rope. Positionedon the mandrel 10, adjacent the ends of the rope 11, are collars 12having annular flanges 13. These members are .em-

ployed in order to form a cylindrical portion at either end of the hosefor the attachment of suitable couplings, and they are also adsvantageous to facilitate the removal of the hose from the mandrel in amanner which will-be subsequently ap arena? A ply of rubberized abric14, preferably cut on a bias, is then wrapped looselyover the helicallyarranged rope 11, with its edges overlapping the flanges 13 on thecollars 12.

While it is preferred to apply the fabric ply 14 cylindrically,satisfactory results may also be obtained by Wrapping the fabrichelically around the mandrel. Theloose end of the rubberized fabric 14may be secured to. the body thereof by attaching it to a gum strip or'aribbon of. un'vulcanized tacky rubber.

-Wlien' the fabric ply lhlS so positioned, it is pulled tightly nto thespaces between the successive convolutions of the rope 11,

' .preferably by means of a wire 15, which is also employed as areinforcing element. The wire should have suflicient temper to lie snug-1y against the fabric, and it should be ap- 1 lied with sufficient forceto remove the ooseness in the fabric 14, and to cause it to followclosely. the contour of the mandrel '10 with the rope 11 positionedthereon. This forcing elements disposed at the crests and the troughs ofthe successive convolutions. An additional wrappinglor outer ply 17' ofbias cut rubberized fabric is then positioned over the mandrel in thesame manner as the inner envelope or ply 14, as illustrated in Fig. 2

To plied a helical wrapping of fabric 18, which is wound tightly uponthe conduit and which is pulled into place by means of a rope 19, thatis also helically wound upon the-mandrel to follow the intervals betweenthe convolutions of the inner rope 11. The rope 19 is secured inposition, and the mandrel 10, with the hose assembled thereon, is thensubjected to a vulcanizing temperature, in order to form a unitaryarticle.

When the vulcanizing operation is completed, the rope 19, thefabricwrapping'18, and the collars 12 are removed. The mandrel 10 is thenwithdrawn from within the hose, an operation which is facilitatedbyapplying air pressure in the space between the inner ply 14 and the faceof the mandrel 10 adacent the end of the hose. If it be found thatdifliculty is experienced in removing the conduit, graphite maybeapplied to the surface of the mandrel, before the assembl is undertaken.This material serves to lu ricate the surface of the cylinder 10 andhence, facilitates its subsequent removal. l

- The rope 11"may then be pulled from the interior ofthe hose to leavethe finished arthe assembly thus formed, there is ap-.

t'icle, shownin fragmentary section in Fig. 4. It will be apparent fromthis view that there is provided a corrugated conduit of unitaryconstruction,'which is highly flexible, and which is reinforced againstloads applied either radially inwardly or outwardly by means of thehelical convolutions or reinforcing-wires 15 and 16. The wiresthemselves are protected from displacement, inasmuch as they are whollydisposed between the plies of fabricmaterial 14 and 17 constituting thewalls of the conduit. The tubing is relatively light in weight, flexibleand resistant to crushing. forces.

From the foregoing description it will be apparent that an efficientmethod has been provided for making a flexible conduit ca-' pable ofwithstanding heavily imposed radial loads. Itis obvious that the methodneed not be followed in all of its details. The invention should belimited only as set forth in the appended claims.

What I claim is:

1. The method of making a flexible conduit comprising applying anenvelope to a mandrel having a helical corrugation defined therein,helically applying elongate reinforcing members to the envelope over thecrests and troughs of the helix respectively to define the latter in theenvelope, applying an outer cover to the envelope and reinforcingmaterial, and securing the parts to each other.

2. The method of making conduits which comprises forming a raised helixon a cylindrical mandrel, so applying an envelope of bias cut rubberizedfabric to the mandrel as to conform to the shape of the helix, applyingreinforcing wires to the crests and troughs of the fabric, applying anouter ply of bias cut rubberized fabric, applyin pressure to the outerply to cause it to conform to the shape of the helix, andvulcanizingunder heat and pressure to form a flexible conduit having a highresistance to crushing loads.

3. The method of making a flexible conduit which comprisesapplylng arubberized envelope to a mandrel having a helical corrugation definedtherein, helically winding an elongate member over the envelope betweenthe crests of the corrugations, applying an outer rubberized cover tothe envelope to correspond to the surface of the latter and the elongatemembers, vulcanizing the assembly into a unit, and finally removlng theunit from themandrel.

4. The method of makin a flexible conduit which comprises applying arubberized envelope to a mandrel having a member helically disposedthereon, applying a rubberized envelope over the helix, winding elongate.reinf-orcing members between the convolutions of the helix therebyconforming the envelope to the latter, applying an outer rubberizedenvelope over the first :envelope and reinforcin members, Vulcanizingthe assembly a-nd ally removing the conduit from the mandrel and thefirst mentioned helical member from the inner wall of the conduit.

In witness whereof, I have hereunto signed my name.

Signed 'at Akron, in the county of Summit, and State of Ohio, this 19thday of October, 1927.

ELMER G. KIMMICH.

